<?php

/**
 * KCAPTCHA PROJECT VERSION 1.2.5
 * Automatic test to tell computers and humans apart
 * 
 * Copyright by Kruglov Sergei, 2006, 2007
 * www.captcha.ru, www.kruglov.ru
 * 
 * System requirements: PHP 4.0.6+ w/ GD
 * 
 * KCAPTCHA is a free software. You can freely use it for building own site or software.
 * If you use this software as a part of own sofware, you must leave copyright notices intact or add KCAPTCHA copyright notices to own.
 * As a default configuration, KCAPTCHA has a small credits text at bottom of CAPTCHA image.
 * You can remove it, but I would be pleased if you left it. ;)
 * 
 * See kcaptcha_config.php for customizing
 * 
 * Who Modified
 * 
 * @license GNU GPL Version 3
 * @copyright 2009, Peter Gribanov
 * @link http://peter-gribanov.ru/license
 * @package	FormManager
 * @author Peter Gribanov
 * @since 06.09.2011
 * @version 1.3
 */
class Captcha {

	/**
	 * Do not change without changing font files!
	 * 
	 * @var string
	 */
	private $alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

	/**
	 * Folder with fonts
	 * 
	 * @var string
	 */
	private $fontsdir = 'fonts';

	/**
	 * JPEG quality of CAPTCHA image (bigger is better quality, but larger file size)
	 * 
	 * @var integer
	 */
//	private $jpeg_quality = 100;

	/**
	 * @var string
	 */
	private $keystring = '';

	/**
	 * Параметры
	 * 
	 * @var array
	 */
	private $optinos = array();


	/**
	 * Enter description here ...
	 * 
	 * @return void
	 */
	public function __construct(){
		$this->optinos = array(
			'allowed_symbols'		=> Options::getOption('form', 'allowed_symbols'),
			'length'				=> Options::getOption('form', 'length'),
			'width'					=> Options::getOption('form', 'width'),
			'height'				=> Options::getOption('form', 'height'),
			'fluctuation_amplitude'	=> Options::getOption('form', 'fluctuation_amplitude'),
			'spaces'				=> Options::getOption('form', 'spaces'),
			'foreground_color'		=> Options::getOption('form', 'foreground_color'),
			'background_color'		=> Options::getOption('form', 'background_color'),
			'image_type'			=> Options::getOption('form', 'default_image_type')
		);
	}

	/**
	 * Устанавливает ширину картинки
	 * 
	 * @param integer $width
	 * @throws InvalidArgumentException
	 * @return void
	 */
	public function setWidth($width){
		if (!$width || !is_numeric($width))
			throw new InvalidArgumentException('Incorrect width of the image.');
		$this->optinos['width'] = intval($width);
	}

	/**
	 * Устанавливает высоту картинки
	 * 
	 * @param integer $height
	 * @throws InvalidArgumentException
	 * @return void
	 */
	public function setHeight($height){
		if (!$height || !is_numeric($height))
			throw new InvalidArgumentException('Incorrect height of the image.');
		$this->optinos['height'] = intval($height);
	}

	/**
	 * Устанавливает количиство символов на картинке
	 * 
	 * @param integer $length
	 * @throws InvalidArgumentException
	 * @return void
	 */
	public function setLength($length){
		if (!$length || !is_numeric($length))
			throw new InvalidArgumentException('Incorrect number of characters in the image.');
		$this->optinos['length'] = intval($length);
	}

	/**
	 * Устанавливает тип выводимого изображения
	 * 
	 * @param string $type
	 * @throws InvalidArgumentException
	 * @return void
	 */
	public function setImageType($type){
		if (!$type || !is_string($type))
			throw new InvalidArgumentException('Incorrect type of image.');
		if (!preg_match('/^(jpg|png|gif)$/i', $type))
			throw new InvalidArgumentException('Unsupported image type.');
		$this->optinos['image_type'] = strtolower($type);
	}

	/**
	 * Гененрирует картинку с кодом
	 *  
	 * @return	void
	 */
	public function getImage(){
		
		$alphabet_length = strlen($this->alphabet);
		$fonts = $this->getFonts();

		while(true){
			$this->genKeyString();
			$font_file=$fonts[mt_rand(0, count($fonts)-1)];
			$font=imagecreatefrompng($font_file);
			imagealphablending($font, true);
			$fontfile_width=imagesx($font);
			$fontfile_height=imagesy($font)-1;
			$font_metrics=array();
			$symbol=0;
			$reading_symbol=false;

			// loading font
			for($i=0;$i<$fontfile_width && $symbol<$alphabet_length;$i++){
				$transparent = (imagecolorat($font, $i, 0) >> 24) == 127;

				if(!$reading_symbol && !$transparent){
					$font_metrics[$this->alphabet{$symbol}]=array('start'=>$i);
					$reading_symbol=true;
					continue;
				}

				if($reading_symbol && $transparent){
					$font_metrics[$this->alphabet{$symbol}]['end']=$i;
					$reading_symbol=false;
					$symbol++;
					continue;
				}
			}

			$img=imagecreatetruecolor($this->optinos['width'], $this->optinos['height']);
			imagealphablending($img, true);
			$white=imagecolorallocate($img, 255, 255, 255);
			$black=imagecolorallocate($img, 0, 0, 0);

			imagefilledrectangle($img, 0, 0, $this->optinos['width']-1, $this->optinos['height']-1, $white);

			// draw text
			$x=1;
			for($i=0;$i<$this->optinos['length'];$i++){
				$m=$font_metrics[$this->keystring{$i}];

				$y=mt_rand(-$this->optinos['fluctuation_amplitude'], $this->optinos['fluctuation_amplitude'])+($this->optinos['height']-$fontfile_height)/2+2;

//				if(!$this->optinos['spaces']){
//					$shift=0;
					if($i>0){
//						$shift=1000;
						for($sy=7;$sy<$fontfile_height-20;$sy+=1){
							//for($sx=$m['start']-1;$sx<$m['end'];$sx+=1){
							for($sx=$m['start']-1;$sx<$m['end'];$sx+=1){
				        		$rgb=imagecolorat($font, $sx, $sy);
				        		$opacity=$rgb>>24;
								if($opacity<127){
									$left=$sx-$m['start']+$x;
									$py=$sy+$y;
									if($py>$this->optinos['height']) break;
									for($px=min($left,$this->optinos['width']-1);$px>$left-12 && $px>=0;$px-=1){
						        		$color=@imagecolorat($img, $px, $py) & 0xff;
										if($color+$opacity<190){/*
											if($shift>$left-$px){
												$shift=$left-$px;
											}*/
											break;
										}
									}
									break;
								}
							}
						}/*
						if($shift==1000){
							$shift=mt_rand(4,6);
						}*/

					}
//				}else{
					$shift=-$this->optinos['spaces'];
//				}
				imagecopy($img,$font,$x-$shift-1,$y,$m['start'],1,$m['end']-$m['start'],$fontfile_height);
				$x+=$m['end']-$m['start']-$shift;
			}
			if($x<$this->optinos['width']-10) break; // fit in canvas
			
		}
		$center=$x/2;

		// credits. To remove, see configuration file
		$img2=imagecreatetruecolor($this->optinos['width'], $this->optinos['height']);
		$foreground=imagecolorallocate($img2, $this->optinos['foreground_color'][0], $this->optinos['foreground_color'][1], $this->optinos['foreground_color'][2]);
		$background=imagecolorallocate($img2, $this->optinos['background_color'][0], $this->optinos['background_color'][1], $this->optinos['background_color'][2]);
		imagefilledrectangle($img2, 0, 0, $this->optinos['width']-1, $this->optinos['height']-1, $background);		
		imagefilledrectangle($img2, 0, $this->optinos['height'], $this->optinos['width']-1, $this->optinos['height']+12, $foreground);

		// periods
		$rand1=mt_rand(750000,1200000)/10000000;
		$rand2=mt_rand(750000,1200000)/10000000;
		$rand3=mt_rand(750000,1200000)/10000000;
		$rand4=mt_rand(750000,1200000)/10000000;
		// phases
		$rand5=mt_rand(0,31415926)/10000000;
		$rand6=mt_rand(0,31415926)/10000000;
		$rand7=mt_rand(0,31415926)/10000000;
		$rand8=mt_rand(0,31415926)/10000000;
		// amplitudes
		$rand9=mt_rand(330,420)/110;
		$rand10=mt_rand(330,450)/110;

		//wave distortion
		for($x=0;$x<$this->optinos['width'];$x++){
			for($y=0;$y<$this->optinos['height'];$y++){
				$sx=$x+(sin($x*$rand1+$rand5)+sin($y*$rand3+$rand6))*$rand9-$this->optinos['width']/2+$center+1;
				$sy=$y+(sin($x*$rand2+$rand7)+sin($y*$rand4+$rand8))*$rand10;

				if($sx<0 || $sy<0 || $sx>=$this->optinos['width']-1 || $sy>=$this->optinos['height']-1){
					continue;
				}else{
					$color=imagecolorat($img, $sx, $sy) & 0xFF;
					$color_x=imagecolorat($img, $sx+1, $sy) & 0xFF;
					$color_y=imagecolorat($img, $sx, $sy+1) & 0xFF;
					$color_xy=imagecolorat($img, $sx+1, $sy+1) & 0xFF;
				}

				if($color==255 && $color_x==255 && $color_y==255 && $color_xy==255){
					continue;
				} else if($color==0 && $color_x==0 && $color_y==0 && $color_xy==0){
					$newred=$this->optinos['foreground_color'][0];
					$newgreen=$this->optinos['foreground_color'][1];
					$newblue=$this->optinos['foreground_color'][2];
				} else{
					$frsx=$sx-floor($sx);
					$frsy=$sy-floor($sy);
					$frsx1=1-$frsx;
					$frsy1=1-$frsy;

					$newcolor=(
						$color*$frsx1*$frsy1+
						$color_x*$frsx*$frsy1+
						$color_y*$frsx1*$frsy+
						$color_xy*$frsx*$frsy);

					if($newcolor>255) $newcolor=255;
					$newcolor=$newcolor/255;
					$newcolor0=1-$newcolor;

					$newred=$newcolor0*$this->optinos['foreground_color'][0]+$newcolor*$this->optinos['background_color'][0];
					$newgreen=$newcolor0*$this->optinos['foreground_color'][1]+$newcolor*$this->optinos['background_color'][1];
					$newblue=$newcolor0*$this->optinos['foreground_color'][2]+$newcolor*$this->optinos['background_color'][2];
				}

				imagesetpixel($img2, $x, $y, imagecolorallocate($img2, $newred, $newgreen, $newblue));
			}
		}
		$this->ptintImage($img2);
	}

	/**
	 * Возваращает список установленных шрифтов
	 * 
	 * @return array
	 */
	private function getFonts(){
		$fonts = array();
		$fontsdir = dirname(__FILE__).'/'.$this->fontsdir;
		if ($handle = opendir($fontsdir)){
			while (false !== ($file = readdir($handle)))
				if (strtolower(pathinfo($file, PATHINFO_EXTENSION))=='png')
					$fonts[] = $fontsdir.'/'.$file;
		    closedir($handle);
		}
		return $fonts;
	}

	/**
	 * Generating random keystring
	 * 
	 * @return void
	 */
	public function genKeyString(){
		while(true){
			$this->keystring='';
			for($i=0;$i<$this->optinos['length'];$i++){
				$this->keystring.=$this->optinos['allowed_symbols']{mt_rand(0,strlen($this->optinos['allowed_symbols'])-1)};
			}
			if(!preg_match('/cp|cb|ck|c6|c9|rn|rm|mm|co|do|cl|db|qp|qb|dp/', $this->keystring)) break;
		}
	}

	/**
	 * Returns keystring
	 * 
	 * @return string
	 */
	public function getKeyString(){
		return $this->keystring;
	}

	/**
	 * Print image
	 * 
	 * @param resource $img
	 */
	private function ptintImage( & $img){
		switch ($this->optinos['image_type']){
			case 'jpg':
			case 'jpeg':
			case 'jpe':
			case 'jfif':
				$this->ptintImageJPG($img);
				break;
			case 'png':
				$this->ptintImagePNG($img);
				break;
			case 'gif':
				$this->ptintImageGIF($img);
				break;
			case 'any':
			default:
				if (!$this->ptintImageJPG($img))
					if (!$this->ptintImagePNG($img))
						$this->ptintImageGIF($img);
		}
		unset($img);
	}

	/**
	 * Print image JPG
	 * 
	 * @param resource $img
	 * @return boolean
	 */
	private function ptintImageJPG( & $img){
		if (function_exists('imagejpeg')){
			header('Content-Type: image/jpeg');
			imagejpeg($img, null, 100);
			return true;
		}
		return false;
	}

	/**
	 * Print image PNG
	 * 
	 * @param resource $img
	 * @return boolean
	 */
	private function ptintImagePNG( & $img){
		if (function_exists('imagepng')){
			header('Content-Type: image/x-png');
			imagepng($img);
			return true;
		}
		return false;
	}

	/**
	 * Print image GIF
	 * 
	 * @param resource $img
	 * @return boolean
	 */
	private function ptintImageGIF( & $img){
		if (function_exists('imagegif')){
			header('Content-Type: image/gif');
			imagegif($img);
			return true;
		}
		return false;
	}

}
?>